The present invention relates to pharmaceutical compositions comprising polysaccharides extracted from a plant source and their uses. In particular, the present invention relates to ophthalmic pharmaceutical compositions comprising a polysaccharide extracted from a plant source and their uses to provide relief to eye conditions such as eye discomfort or irritation. More particularly, the present invention relates to ophthalmic pharmaceutical compositions comprising a polysaccharide extracted from mushrooms and their use to provide relief to a dry eye condition.
Many environmental factors can negatively affect the health of the eye. For example, allergens, irritants (such as chemicals), viruses, and bacteria can result in redness, irritation, or inflammation of the conjunctiva. Diseases from other parts of the body also can affect the eye. Dry eye (also known as keratoconjunctivitis sicca (“KCS”)), a disorder manifested as insufficient tear film for lubrication of the ocular surface, can be the result of environmental factors or diseases. Dry eye affects millions of people each year. There has been increasing evidence that inflammation may be an important factor in the pathogenesis of KCS. For example, inflammation of the lacrimal and meibomian glands can curb tear production. In addition, elevated levels of pro-inflammatory mediators, including IL-1, have been detected in the conjunctival tissues of patients afflicted with systemic autoimmune diseases, such as Sjögren's syndrome. Sjögren's syndrome is a chronic disorder in which white blood cells attack the moisture-producing glands, such as lacrimal and salivary glands. Dry eye may afflict individuals with differing severity. In mild cases, a patient may experience burning, a feeling of dryness, and other symptoms of ocular discomfort. In severe cases, vision may be substantially impaired. Although dry eye may have a variety of unrelated pathogenic causes, they all share as a common effect the breakdown of the ocular tear film, with dehydration of and subsequent damage to the exposed outer ocular surfaces.
These pathological conditions produce significant discomfort in the eye, such as itching or burning sensation, which can benefit from relief by palliative agents. Many such agents have been provided with varying success. The relief that they provide are often short-lived. In addition, prior-art compositions do not effectively provide many benefits of the natural tear. Therefore, there is a continued need to provide improved ophthalmic compositions for the relief of ocular discomfort. It is also very desirable to provide such compositions for an extended relief of ocular discomfort such as the dry eye condition.